When hollow organs such as blood vessels or the intestine become pathologically altered, for example as a result of growth of malignant or benign tumors or polyps, or as a result of deposits in vessels, the pathological tissue or the deposits are often removed by performing invasive procedures. This is done either surgically or via invasive catheterization. A particular problem in this connection is that the pathological processes are chronic, i.e. the tissue lesions or deposits reappear after just a few weeks or months (a phenomenon called restenosis). Thus, it is necessary to repeat procedures which are expensive and which place a physical burden on the patient. Another factor is that in many cases the areas of the hollow organs to be treated, for example in the small intestine, cannot be reached from outside by catheter.